Take a dazzling architectural journey inside those majestic marvels of Gothic architecture, the great cathedrals of Chartres, Beauvais and other European cities. Carved from 100 million pounds of stone, some cathedrals now teeter on the brink of catastrophic collapse. To save them, a team of engineers, architects, art historians, and computer scientists searches the naves, bays, and bell-towers for clues.